Chapter 6 X-ray Imaging System 3- main parts X-ray tube, operating console and high voltage generator

Usual voltage 25-150 (25-40 for mammo) Currents 100-1200/1500 mA RAD tube usually overhead Fluoro tube usually under the table Must be radiolucent – usually made of carbon fiber and 250-300 lb max. Most are “floating” Fluoro tables must have a “bucky hinge” (1/4 mm pb equiv for protection) and are usually 90/30 tables

Consoles Most are micro-mini computer ALL are LOW VOLTAGE (kVp meter is a pre-reading voltmeter) Line voltage compensator kVp – major/minor mA

Timers Mechanical (least accurate) Synchronous impulse mAs (only timer in the high voltage circuit) AEC

Hi Voltage Transformer Turns ratio – P is always on your left and S on your right Only work with A/C current

Rectification ½ wave unmodified 60 cycle/sec current 60 impulses per second Full wave rectified (pulsed DC) 120 impulses per second Self rectified (same as half wave, BUT it’s the x-ray tube that does the rectification

3-phase power Placing 3 separate ac sine waves over each other in an “out of phase fashion” (3 each A/C 60 cycle/sec waves) Creates a “ripple effect” (watch the wording of any questions with “ripple” as they can be tricky – of course, not mine!) 3 phase, 12 pulse = 100% ripple 3 phase, 6 pulse = 14% ripple

Be able to draw and label the circuit as shown on P.117!